Research Initiation: Ultra-Precision Machining of Glass Components

该项目旨在推进玻璃的高精度研磨技术，即“延性区域研磨”，旨在消除表面断裂和亚表面损伤。有了这项新技术，许多以前因脆性而难以加工成准确形状的材料现在可以在一次磨削操作中加工成镜面抛光。这种改进的材料去除过程是通过将磨削进给速度控制在每砂轮旋转100纳米以下而实现的。这一工艺适应了延展性区域，即使是上述新技术也不能完全消除玻璃研磨过程中的表面断裂。提出了在砂轮和工件之间引入金刚石抛光液，一次加工即可生产出高精度的光学玻璃零件。将抛光液引入研磨区的另一个好处是，它将允许对大型(大于1米)光学元件进行超精密研磨，这一应用以前被认为是不可能的，因为在玻璃加工中，钻石砂轮会迅速变钝。在这种应用中，联合研磨/抛光方法具有相当大的优点：通过不断修整砂轮，松散的磨料解决了砂轮钝化的问题。同时，磨削提供了对刀具位置的精确控制，克服了在抛光操作中遇到的固有轮廓误差。

This project is to advance the technology of high-precision grinding of glass, known as "ductile regime grinding", with the specific aim of eliminating surface fracture and subsurface damage. With this new technology, many materials that have previously been difficult to machine to accurate shapes because of their brittleness can now be machined to mirror finishes in a single grinding operation. This improved material-removal process is made possible by controlling the grinding infeed to rates below 100 nanometers per grinding wheel revolution. This process adapts the ductile-regime, and even the new technology described above cannot completely eliminate surface fracture during the grinding of glass. It is proposed that by introducing a diamond polishing slurry between the grinding wheel and the workpiece, high precision optical-quality glass components could be produced for the first time with a single machining operation. An additional benefit resulting from the introduction of a polishing slurry into the grinding zone is that it will permit ultra-precision grinding of large (greater than 1 meter) optical components, an application that has previously been considered to be impossible because of the rapid dulling of the diamond grinding wheel in the machining of glass. In this application, the combined grinding/polishing approach has considerable merit: by continually dressing the wheel, the loose abrasive solves the problem of grinding wheel dulling. At the same time, the precise control of tool position offered by grinding overcomes the inherent contour inaccuracies that are encountered in polishing operations.